What data types should be avoided for indexing in a database?

For indexing in a database, it is better to avoid the following data types:

• Text fields with large length (e.g., TEXT, BLOB), as indexes on them occupy a lot of space and work slowly.
• Floating types (float, double), because of the peculiarities of storing and comparing floating-point numbers, indexes may work incorrectly or inefficiently.
• Types with high volatility or low selectivity, such as boolean fields or fields with very few unique values, as indexes on them are less effective.

It is better to use fixed-length types with high selectivity, such as integer types (INT, BIGINT) or short strings (VARCHAR with limited length).